1. Field of the Invention
The present invention relates to a thermoplastic polyhydroxy polyether which has flame retardancy by containing phosphorus, which is useful in the electric field or electronic field such as a laminated board for electric equipment, a magnetic tape binder, an insulating varnish, and a self welding enamel electrical-wire varnish, adhesive field, an insulating coating or film field, further relates to an insulating film produced from said resin.
2. Description of the Prior Art
The thermoplastic polyhydroxypolyether resin is conventionally known as a phenoxy resin. Because of the excellent flexibility, shock resistance, adhesion and mechanical property which thermoplastic polyhydroxypolyether resin has, said resin is broadly used in the electric or electronic fields for example, a magnetic tape binder, an insulating varnish for electric equipment e.g. electric motor, adhesive for the circuit boards and a film. Especially, in the field in which the safety, e.g. prevention of fire and retardation of a flame is strongly required, the halogenated phenoxy resin was used, especially brominated phenoxy resin was mainly used. However, when the material which used the halogenide is used for long period of time at an elevated temperature, it is known that it will cause the maceration of a halogenide and this will cause the corrosion of a wiring. Further, in the case when the scraps of used electronic parts or electric equipment is burned, toxic substances such as halogen or halogenide are generated. And from the environmental safety view point, the direct or indirect use of hologen is becoming a problem, and the research to investigate the material to provide flame retardancy in stead of halogen are becoming to be carried out. The flame retardant film which uses thermoplastic polyhydroxy polyether resin is disclosed in JP 5-93041A or in JP 5-93042 A publication. Almost all of flame retardancy agents used in these documents are a halogenide, and the flame retardancy by use of phosphorus is not described. As a flame retardant compound which uses phosphorus compounds, a compound described in xe2x80x9cSynthesis and properties of epoxy resins containing 2-(6-oxid-6H-dibenz  less than c,e greater than  less than 1,2 greater than oxaphosphorin-6-yl) 1,4-benzenediolxe2x80x9d by WANG C-S, SHIEH J-Y, Polymer (GBR) VOL.39, NO.23, PAGE 5819-5826 (1998) can be mentioned. However, this compound is using the compound obtained by addition reaction of the phosphorus containing compound with benzoquinone as a reactive flame retardant compound for epoxy resin, which is thermosetting resin. In xe2x80x9cNovel flame retardant epoxy resins. I. Synt-hesisi, characterization, and properties of arylphosphinate epoxy ether cured with diamine.xe2x80x9d by CHO C-S, CHEN L-W, CHIU Y-S, Polymer Bulletin VOL.41, NO.1, PAGE 45-52 (1998), a new epoxy resin is disclosed as a thermosetting resin obtained from a phosphorus containing compound, a benzoquinone and epichlorohydrin. However, in these documents, there is no indication about thermoplastic resin and the insulating film.
The object of the present invention is to provide a thermoplastic polyhydroxy polyether resin which has flame retardant property without using a halogenide and to provide an insulating film formed by using said resin.